The protein encoded by this gene is a serine/threonine kinase that may be involved in the regulation of chromatin assembly. The encoded protein is only active when it is phosphorylated, and this phosphorylation is cell cycle-dependent, with the maximal activity of this protein coming during S phase. The catalytic activity of this protein is diminished by DNA damage and by blockage of DNA replication. Three transcript variants encoding different isoforms have been found for this gene.?